Field of the Invention
The present invention relates to an apparatus for controlling clock signals to be supplied to a plurality of processing modules and a control method thereof.
Description of the Related Art
A technique for controlling a frequency of a clock signal and a power source voltage value to be supplied to a processing module is discussed for optimizing a processing time and reducing power consumption in a system including a plurality of processing modules capable of performing processing in parallel. For example, Japanese Patent Application Laid-Open No. 2002-215599 discusses a multiprocessor system in which a processor A and a processor B respectively execute a program A and a program B in parallel and synchronize with each other after the processing. In this system, for example, the processor A changes a frequency of an input clock signal according to a ratio between a processing time estimated value Ta of the program A and a processing time estimated value Tb of the program B and changes a power source voltage to be supplied according to the frequency of the clock signal. Accordingly, power consumption of the processor A is reduced.
The above-described technique controls a frequency of a clock signal and a power source voltage to be supplied in next processing according to a previously estimated ratio of processing time estimated values or a previous processing time of each processor. According to the above-described technique, it is difficult to appropriately control a frequency of a clock signal and a power source voltage to be supplied to a processing module in processing in which a processing time varies depending on input data, for example.